Routing devices within a network, often referred to as routers, maintain tables of routing information that describe available routes through the network. Upon receiving an incoming packet, the router examines information within the packet and forwards the packet in accordance with the routing information. In order to maintain an accurate representation of the network, routers exchange routing information in accordance with a defined routing protocol, such as the Border Gateway Protocol (BGP).
The term “link” is often used to refer to the connection between two devices on a network. The link may be a physical connection such as a copper wire, a coaxial cable, any of a host of different fiber optic lines or a wireless connection. In addition, network devices may define “virtual” or “logical” links, and map the virtual links to the physical links. In other words, the use of virtual links provides a degree of abstraction.
To avoid link congestion, traffic engineering may be applied within a network for a variety of purposes, such as to route traffic around network failures or congested links. For example, a label switched path (LSP) may be set up in a Multi-Protocol Label Switching (MPLS) network by a resource reservation protocol, such as the Resource Reservation Protocol with Traffic Engineering extensions (RSVP-TE). In this manner, RSVP-TE LSPs may be used to define a path from a source device to a destination device that avoids failures or bottlenecks within the network.
In some cases an LSP spanning multiple domains may be created by “stitching” together independent, intra-domain LSP segments. The term stitching generally refers to binding the end-to-end LSP to the intermediate LSP segments to create the LSP. As a result, the LSP is often referred to as an “end-to-end” LSP that appears as one contiguous LSP, but constitutes multiple LSP segments in actuality. Existing signaling mechanisms for packet-based networks do not to support explicit LSP stitching, and may involve manual configuration.